html,body {
  /* width: 100%; */
  /* overflow: hidden; */
  padding: 0;
  margin: 0;
}

.contain {
  /* width: 1000px; */
  padding: 0 200px;
}
.contain::after {
  content: '';
  display: block;
  clear: both;
  
}
.center,.left,.right{
  float: left;
}
.center {
  background-color: pink;
  width: 100%;
  min-height: 300px;
}

.left,.right {
  width: 200px;
  min-height: 200px;
  background-color: greenyellow;
}
.left {
  position: relative;
  margin-left: -100%;
  left: -200px;
}
.right {
  position: relative;
  margin-left: -200px;
  right: -200px;
}